Rutting potential of thin and durable asphalt wearing courses: Laboratory prediction and field performance

Alternative asphalt concrete (AC) mixtures have been developed to provide thin, durable, efficient, and cost-effective wearing courses. A combination of locally available and durable aggregates, such as steel slag and quartzite, were used to enhance the performance of the mixes while ensuring cost effectiveness. In addition, fibers were used in a new mixture for potential reduction in the AC layer thickness due to the increase in its tensile strength. In addition, several innovative approaches to develop new AC mixtures were also introduced and evaluated. Four new AC mixtures and two control mixtures were placed in the Chicago area to evaluate their field performance under real traffic loading. This paper focuses on the permanent deformation of the newly developed AC mixtures and presents their rutting potential based on laboratory testing and their short-term rutting performance in the field. Wheel tracking testing was conducted on each AC mixture. The specimens were prepared using two mixing approaches: lab-mixed and lab-compacted specimens and plant-mixed and lab-compacted specimens. A dipstick was used to measure rut depth in the field every four months after construction. To evaluate the effect of layer thickness on measured permanent deformation, two sections having different layer thicknesses were constructed for each AC mixture. This paper presents the difference in rutting potential based on laboratory testing and field measurement for the newly developed wearing surface AC mixtures and the effect of layer thickness on rutting development.